The present invention relates to a rear vehicle-body structure of a so-called open car provided with an openable roof.
Vehicles with an openable roof (convertible type open car) have been developed, and examples of those vehicles are disclosed in International Publication No. WO 2005/061253 A1 and Japanese Patent Laid-Open Publication No. 2007-261405.
As shown in FIGS. 13-15, an automotive vehicle 100 disclosed in the above-described first patent document comprises a foldable roof 100, a housing 102 to store the foldable roof 101 (see FIG. 14), and a lid 103 to close an opening portion of the housing 102. The lid 103 comprises a plate-shaped base portion 104 and a pair of vertical fins 105 which are provided at both sides, in a vehicle width direction, of the base portion 104. The base portion 104 comprises a central portion 104a which is of a rectangular shape in a plan view and a pair of side portions 104b which are integrally formed at both sides, in the vehicle width direction, of the central portion 104a. Each of the side portions 104b protrudes rearward beyond the central portion 104a in the plan view (a rear portion of the base portion 104 is of a concave shape in the plan view). The vertical fin 105 is configured to protrude upward at the side portion 104b of the base portion 104 and extend in a vehicle longitudinal direction. The vertical fin 105 is of a right triangular shape, when viewed from a vehicle side, such that the hypotenuse of the right triangle slants rearward and downward. An acute-angle portion 105a of the right triangle which has the smallest angle is positioned at a rear end portion of the side portion 104b. 
The both-side side portions 104b of the base portion 104 are rotatably attached to a back face of a rear deck 107 via arc-shaped hinges 106 (see FIG. 14). The arc-shaped hinge 106 is a so-called swan hinge, and its one end portion is rotatably attached to a lower face of the rear deck 107 around a horizontal axis, and its other end portion is fixed to a lower face of the side portion 104b of the base portion 104.
A flat-shaped transparent panel 109 which forms a rear window of a passenger cabin 108 is arranged vertically at a border of the passenger cabin 108 and the base portion 104. The transparent panel 109 is guided by a vertical side guide portion (not illustrated) at its both-side end portions so as to move vertically.
The transparent panel 109 is configured to partition the passenger cabin 108 from a space formed between the right and left vertical fins 105 in a state in which the transparent panel 109 is pulled out upward.
For a transition from the closed state in which the foldable roof 101 covers over the passenger cabin 108 (see FIG. 13) to the open state in which the foldable roof 101 is stored in the housing 102 (see FIG. 15), the lid 103 is opened as shown in FIG. 14, then the foldable roof 101 is folded into the housing 102, and finally the lid 103 is closed (see FIG. 15).
According to the automotive vehicle 100 of the above-described first patent document, the vertical fin 105 creates a coupe-style appearance at a rear portion of the vehicle in a side view, so that the automotive vehicle 100 equipped with the roof can be superior (excellent) in design. Further, a driver can view (see) backward through the transparent panel 109.
The above-described second patent document discloses an automotive vehicle which comprises a retractable roof, a storage space to store the retractable roof, an openable lid to cover an opening portion of the storage space, and a link mechanism connecting the lid and a bottom portion of the storage space.
The above-described link mechanism is a mechanism to open or close the lid. The link mechanism is configured to be folded in a state in which the retractable roof is stored in the storage space (an open state) and in a state in which the retractable roof covers over the passenger cabin (a closed state).
Meanwhile, in the transition from the open state to the closed state, and in the transition from the closed state to the open state, the link mechanism rises up and the lid goes up, moving rearward, relative to the opening portion of the storage space.
According to the automotive vehicle of the above-described second patent document, since the lid goes up, moving rearward, relative to the opening portion of the storage space, the retractable roof can be stored in the storage space through the opening portion.
However, in the automotive vehicle 100 of the above-described first patent document, since the right-and-left vertical fins 105 are merely interconnected at respective lower end portions, the lid 103 does not have a sufficient (high) rigidity.
Herein, in a case in which the lid 103 is configured move by using the link mechanism shown in the above-described second patent document in place of the hinges 106, there is a problem that a twist of the lid 103 may be generated during the moving because of the insufficient (low) rigidity of the lid 103, so that the stability of the move may be deteriorated.